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zimovet [89]
4 years ago
15

john is twice as old as mary. the sum of their ages is 21. how old is mary? let j = john's age and m = mary's age. select the sy

stem equations that represents the problem.
Mathematics
1 answer:
Verdich [7]4 years ago
3 0
Hello,

let's assume j the john's age, m the mary's age.

<span>"John is twice as old as mary"==>j=2*m
</span>
<span>"the sum of their ages is 21" ==>j+m=21

==>2*m+m=21
==>3m=21
==>m=7
and j=21-7=14

</span>
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What are the x- and y-intercepts for the graph of −5x − 4y = −20? Plz explain your answer.
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8 0
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As the calculated F lies in the acceptance region therefore we conclude that there is not sufficient evidence to support the claim that the variability in concentration may differ for the two companies. Hence Ha is rejected and H0 is accepted.

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n1=10    s1=4.7

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And α = 0.05.

The null and alternate hypothesis are

H0: σ₁²=σ₂²       Ha:  σ₁²≠σ₂²

The null hypothesis is  the variability in concentration does not  differ for the two companies.

against the claim

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The critical region F∝(υ1,υ2) = F(0.025)9,15= 3.12

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